Variable condenser



Oct. 29, 1929. o. c; DEUTSCHE'R 1,733,337

4 VARIABLE cominusnn v Filed July 19, 1926 2 Sheets-Sheet 1 INI/ENTOR CDggjCi-HER ,4 TTUR NE Y Oct. 29, 1929.

2 Sheets-$heet 2 0 4 Q2225 Y 1 I /W/ I/I I Z i iliin I INVENTOR OSCAR C. DEUTSQHER A TTOR/VE Y Patented Oct. 29, 1929 I UNITED STATES PATENT OFFICE .OSGAR c. nnu'rscnnn, OF BROOKLYN, NEW YORK VARIABLE oonnnnsnn Application filed July 19, 1926. Serial no. 123,278.

This invention relates tdvariable tuning elements as used in connection with radio receiving apparatus and has as one of its objects to provide a straight line frequency condenser having an inductance coil concealed and protected within the structure.

A further-feature is in the provision of a condenser formed primarily of two-conical elements, respectively fixed and movable, by

ill

of anexnbodiment of the invention, taken on line 1-1 otFigv 2. v

Figure 2, is a side elevation of the same. Figure 3, is a top plan view thereof. Throughout the several-views the numeral lddesignates in general a support, such as a conventional panel, having rigidly attached by spacers 11, a bar 12, arranged in parallel at its inner side.

The bar 12 has secured at its ends a pair of. frame sides 13 connected by a platebar 1d at their outer ends and constituting a rigid rectangular nonconducting frame.

The side members 13 are provlded with central longitudinal slots 15 in which areslidablyv contained two pairsof sleeves 16 and 1'Zfhaving flanges 'at each end to retain the bodies of the sleeves withinthe slots.

The pair of sleeves 16, adjacent thebar '12,

carry conduction spindles" 18,; their reduced inner portions supporting an insulating ring 18, comically recessed to receive the base of a metal cone 20, firmly seated therein and held by riveting the ends of the spindles 18 against its inner surface as 21 The other sleeves 17 contain in a similar manner another pair of conducting spindles 22, reduced near their points to engage in a disc 23, in which the smaller end or the cone is fixed anda series of perforations 2 1 formed through the disc 23 admit air to the interior of the cone; I

Another cone 25 has a flange 26 at its base which is rigidly secured to the inner side of the bar 12, to extend outwardly concentric with the cone 2(). Y

A circular dielectric rod or tube/27 containing a hollow core 28 passes freely through the outer bar. 12, axially of-the cones and is provided with a fixed collar 29 impinging against the inner side of the disc 23, through which its reduced threaded portion 80 entends.'-

A clamp nut 31 draws the collar tightly to the disc and on the outer side of the nut is a yoke bar '32 rigidly held by a Washer and clamp nut 33.

Attached at their ends respectively tothe yoke bar 32, and plate barlhof the frame are a pair of coiled tension springs 341, the same. acting to draw the cone 20 and its attachmentsoutwardly away from the inner cone 25 to increase. the air gap space- 35 between the cones,

Connectedby a joint 36 at the outer-end of the tube 27,.is a spindle 36 having a coarse pitch spiral or thread 37 initslouter portion,

in which operates a pin 38 fixed in a sleeve 39 solidly molded into a twirling knob 400i conventional type. v The spindle '39 rotates within a second sleeve 41 screw threaded at its end projecting through the panel 10 anddrawn by a nut i2 to tighten its flange 43 against the outer end of hub 44 formed on a circular index 45 to be held thereby closely against the face of the ipanela The hub contains an annular groove 46 into which enter the points of one or more screws 47 set in the knob and by which it is held to rotate on the hub and index, a

' and that the air gap 35 will be varied directly in proportion to the active area of the cone surfaces involved it will be apparent that all looseness or black lash is eliminated due to the action of the springs 34, thereby rendering the device instantly and fully responsive to any motion communicated to it by the knob 40,

In addition an inductance coil 49 is mounton the tube 27 Within the fixed cone 25 and in fixed relation to the movable cone 20, the coil being" connected in the usual manner and is fully protected by being enclosed within the fixed cone.

Should an apparatus of greater capacity be desirable the cones may be used in multiple, as shown in 3, the structural. features remaining substantially as described.

Thus a variable tuning apparatus of a straight line frequency of unusual merit has been disclosed in the preferred form of its embodiment, but it will be understood that minor changes in construction may be made Without departing from the spirit and scope of the appended claim and that parts thereof may be used in place of the Whole it found desirable. 1

Having thus described my invention and set "forth the manner of its construction. and application, What I claim as new and desire secure by Letters Patent, is

A. variable condenser comprising a rigid rectangular non-conducting frame provided with a bar having secured at its ends a pair of ame side members} longitudinal slots iormed in said side members, tWo pairs of sleeves slidably mounted in said S1Qt$ one of said pair having iianges on each end to retain the sleeves Within the slots, conduction spindles carried by said sleeves adjacent said bar an insulating ring supported by said con duction spindles said insulating ring being onicaily recessed, an outer metal disc cone "mlyseated in the conically recessed por tion of said ring, other conducting spindles contained in said other pair of sleeves, a disc provided with plurality of perforations iii) said perforations being adapted to admit. air he interior of said cone, an. inner metallic rovided with a flange its base adapts r be rigidly secured "to said and ex tended outvvardi concentric ith outer cone 3- ircuiar iectric W rod adapt osoAR c. nEU'rsonER. 

